Locking device for typewriters and like machines



April 7, 1959 G. A. MEssNER ETAL LOCKING DEVICE FOR TYPEWRITEIRS AND LIKE MACHINES Filed May 6, 1957 2 Sheets- Sheet 1 RWQERO E A: M 935R @wb -A'T,TORNEYS I LOCKING DEVICE FOR TYPEWRITERS AND LIKE MACHINES Filed May 6, 1957 2 Sheets-Sheet 2 FIG.2

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INVENTOR RICHARD RCERO GEORGE AME NER 5 BY 1 5W ATTORNEYS United States Patent LOCKING DEVICE FOR TYPEWRITERS- AND LIKE MACHINES George A. Messner, South Windsor, and Richard P. Cero,

West Hartford, Conn., assignors' to Royal McBee CorpYorrition, Port Chester, N.Y.-,. a corporation of New Application May 6, 1957, Serial No. 657,230

6 Claims. (Cl; 197-145) This invention relates to a locking. device for a typewriter or like machine and more particularly relates to a novel mechanism for locking and unlocking bothv the cylindrical platen and an associated portion of the carriage housing of the machine.

After an extended period of use the cylindrical platen of a typewriter may require replacement or repair in which case the platen must beremoved from the typewriter carriage. Here to allow at least one side of the platen supporting. shaft to be" lifted out of the carriage frame, the means for rotatably securing said shaft in said frame, and the associated adjacent portion of the carriage housing must be capable ofbeing moved out of their respective normal operative positions; Conversely, when anew or repaired platen is replaced in. the carriage, the platen shaft securing means must be re stored to its normal locking position and said portion of the carriage housing must be returned to and retained in its normal position wherein it conforms to the contours of the remaining portions of the carriagehousing. If each of these units, i.e. the platen securing. means and the movable carriage housing, were providedv with a separate control handle, thento remove and/or replace the platen would require asimultaneous or serial operation of these handles incombination with a ver-. tical displacement of the platen shaft. In either case the excessive amount of manual manipulation required would make the operation tedious and bothersome.

One object of the invention is to provide an easily operated locking mechanism for both the platen shaft and the adjacent portion of. the carriage housing of a typewriter or like machine.

Another object of the invention is to provide a novel platen securingmeans which will. be automatically operated to its locked position when the platen shaft is laterally inserted into the machine;

A further object of the invention is to provide a locking mechanism for automatically effecting a locking and unlocking of a movable portion of the carriage housing in response to a lateral movement of the platen shaft.

Other objects will appear as the disclosure progresses.

For a more detailed description of the preferred embodiment of the invention reference is made to the drawings wherein:

Fig. 1 is a perspective view of the locking mechanism for the platen and housing of a typewriter carriage, and shows the various parts of said mechanism in their respective normally closed or locked positions, and

Fig. 2 is a right side elevation of the locking mechanism illustrated in Fig. l, and shows said parts in their respective open or unlocked positions.

The various component parts of a typewriter carriage which are not pertinent to the instant invention have been omitted from the drawings for the sake of clarity. It will be understood that unless otherwise stated the parts shown are suitably supported on the carriage frame in a manner well known in the art.

Referring to Fig. 1 there is shown a typewriter base 2,380,839 Patented. Apr. 7,, 1959 6 on which is: movably mounted a carriage frame 8. Fastened. to said frame 8- is the usual fixed housing 10. A. vertically disposed side plate 12- is secured by any suitable means to the right hand end of carriage frame 8. Integrally formed. on the forward edge of plate 12 isan upstanding. arm 14- and a. bent over U-shaped bracket 16 the terminal: portion 18 of which is vertically disposed and is horizontally spaced to the right with respect. to the main body of plate 12.. A U-shaped bracket- 20 is pivotally mounted on side plate 12 by means of theaxially aligned studs- 22- and 24 secured to the arm- 14 and bracket 16 respectively. The contoured housing. 30 is secured byany suitable means to the extension 32' of the pivoted bracket 20 whereby said housing 30 may be swinga'bly moved intoand out of aligned engagementwith said. fixedhousing 10. The right hand leg 34 of said bracket 20 has integrally formed therein a rearwardly facing shoulder 36 and bent over ears 38 and 40.

To the right hand end ofv the platen 46 is secured a supporting shaft 48 having a. bearing collar 49 rotatably mounted thereon. The bearing collar 49- is seated in the bearing groove 50 of. side plate 12.. A locking lever 52, pivotally mounted on the sideplate arm 14 by means of stud 54-, is: biased: in. a. counterclockwise direction by means of spring 56 so that the lockingv shoulder 58 of said lever normally engages the bearing collar 49 and secures the latter in said. bearing groove 50.. On the rearward edge 06 said lever 52, immediately above said shoulder 58, there is provided a c'arn-ming. surface 60the purpose of which will be subsequently explained. A stud 55 secured to the frame plate 12 serves to limit the counterclockwise movement of! the lever 52-.

Pivotally mounted. on said. stud 24 of side plate 12 is a bifurcated latch 62 whose two arms 64 and 66 normally straddle the bearing collar 49. The bent over car 68 of said latch is connected to said car 40 of bracket 20 by means of a spring 70. A slot 72 in the latch 62 slidably receives said bent over ear 38- of the bracket 20 to thereby limit the relative rotative movement between the movable housing support bracket 20 and the bifurcated latch. 62.

In the normal locked condition of the parts, Fig. l, the platen shaft 48 and the" collar 49 are secured in the bearing groove 50 by means of said locking shoulder 58. Spring 70 yieldingly maintains the lower arm 66 of latch 62 in engagement with collar 49 and also yieldingly maintains said movable housing 38 in aligned engagement with the fixed housing 10.

When it is desired to remove the platen 46 from the typewriter carriage, lever 52 is manually rotated in a clockwise direction. Here the shoulder 58 will be moved to the left thereby freeing the platen shaft 48 for vertical displacement. During the initial upward movement of shaft 48 the spring 70 will cause the arm 66 of latch 62 to follow upward displacement of said shaft until the bent over ear 68 of said latch engages the rearward shoulder 36 of the housing bracket 20. During the continued upward movement of shaft 48, collar 49 will engage the upper arm 64 of latch 62 and will rotate the latter counterclockwise thereby pivoting the movable housing 30 away from said fixed housing 10 to an open position, Fig. 2, which is determined by the engagement of the lower edge 74 of said housing 30 with the U- shaped bracket 16 of side plate 12. In the open or unlocked condition of parts as shown in Fig. 2 neither the movable housing 30 nor the arm 64 of latch 62 block the further upward movement of platen shaft 48. After the right hand end of said shaft has been lifted clear of the carriage frame the left end of the platen 46 may be subsequently removed from its supporting structure by moving said platen axially in a manner well known in the art.

When a new or repaired platen is to be replaced in the typewriter carriage, the left end of the platen is rotatably secured to the carriage in the usual (fashion and the shaft 48 is lowered into the bearing groove 50. During its downward movement,- collar 49 will initially engage the lower arm 66 of latch 62 and will rotate the latter, together with the movable housing 30, in a clockwise direction. Shortly after engaging said latch arm 66, collar 49 will engage the angularly disposed camming surface 60 of lever 52 and will pivot said lever in a clockwise direction. When said collar has seated in the bearing grooves 50 the locking shoulder 58 of lever 52 will move counterclockwise to its locking position shown in Fig. 1 under the action of spring 56. Meanwhile the movable housing 30 will have been rotated by latch 62 and bracket 20 to its closed or locked position. In this condition of the parts spring 70 will be slightly tensioned so as to yieldingly maintain the movable housing 30 in aligned engagement with the fixed housing 10.

It will be seen that moving the lever 52 clockwise from the normal position of Fig. 1 unlocks the platen shaft 48 for vertical movement and the upward displacement of the latter automatically unlocks and displaces the movable housing 30. Conversely when the platen shaft 48 is moved downwardly into the bearing groove 50 it will pick up and move the housing 30 to the closed position and will itself be automatically detented under the latch shoulder 58. Thus when removing the platen only one control handle, lever 52, need be manipulated; and when replacing the platen no control handles need be moved. The above described locking mechanism is sufficiently simple and reliable to be efiicient in operation.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration only and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

The invention claimed is:

1. In a typewriter having a carriage frame, a main housing secured to said frame, a cylindrical platen, and a supporting shaft secured to said platen and rotatably mounted on said frame; the improvement comprising a movable housing mounted on said frame and adjacent said shaft, and means on said frame cooperating with said shaft for locking said movable housing in a position adjacent said main housing.

2. In a typewriter carriage having a frame, a cylindrical platen provided with a supporting shaft which is rotatably mounted on said frame, and a main housing secured to said frame; the improvement comprising a movable housing mounted on said frame adjacent said shaft, a spring biased latch connected to said movable housing, and means on said latch cooperating with said shaft for maintaining said movable housing in aligned engagement with said main housing.

3. In a typewriter having a carriage frame, a main housing fixed on said carriage frame, and a cylindrical platen having a supporting shaft which is rotatably mounted on said frame; the improvement comprising means for detachably securing said shaft on said frame, a movable housing mounted on said frame and adjacent said shaft, and means connected to said movable housing and cooperating with said shaft for retaining said movable housing in aligned engagement with said main housing.

4. In a typewriter having a carriage frame, a main housing fixed on said frame, and a cylindrical platen having a supporting shaft which is rotatably mounted on said frame; the improvement comprising means for detachably securing said shaft to said frame, a movable housing pivotally supported on said frame adjacent said shaft, and a spring biased latch means connected to said movable housing and cooperating with said shaft for yieldingly retaining said movable housing in aligned engagement with said main housing.

5. In a typewriter having a carriage frame, a main housing fixed to said frame, and a cylindrical platen having a supporting shaft which is rotatably mounted on said frame; the improvement comprising a detent lever pivotally mounted on said frame, spring means normally biasing said lever to a position for detachably securing said shaft to said frame, a movable housing pivotally mounted on said frame adjacent said shaft, and a spring biased latch connected to said movable housing and cooperating with said shaft for retaining said movable housing in aligned engagement with said main housing.

6. In a typewriter having a carriage frame, a main housing fixed to said frame, and a cylindrical platen having a supporting shaft rotatably mounted on said frame; the improvement comprising a lever pivotally mounted on said frame, a locking shoulder and an angularly disposed camming surface formed on said lever, said cam surface serving to pivot said lever in response to a downward lateral movement of said supporting shaft, spring means normally biasing said lever to a position wherein said locking shoulder overlies said shaft, a movable housing pivotally mounted on said frame, a bifurcated latch pivotally mounted on said frame and cooperating with said shaft, and spring means operatively connected between said latch and movable housing for yieldingly maintaining said movable housing in aligned engagement with said main housing.

References Cited in the file of this patent UNITED STATES PATENTS Helmond Dec. 26, 1944 

